/*
 ** Copyright 2001, Travis Geiselbrecht. All rights reserved.
 ** Distributed under the terms of the NewOS License.
 */
/* Code modified by Justin Smith 2003/06/26 */

#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <ctype.h>
#include <stdio.h>
#include <sys/types.h>

#if 0
static unsigned long simple_strtoul(const char *cp,char **endp,unsigned int base)
{
    unsigned long result = 0,value;

    if (!base) {
        base = 10;
        if (*cp == '0') {
            base = 8;
            cp++;
            if ((*cp == 'x') && isxdigit(cp[1])) {
                cp++;
                base = 16;
            }
        }
    }
    while (isxdigit(*cp) && (value = isdigit(*cp) ? *cp-'0' : (islower(*cp)
                                                               ? toupper(*cp) : *cp)-'A'+10) < base) {
        result = result*base + value;
        cp++;
    }
    if (endp)
        *endp = (char *)cp;
    return result;
}

static long simple_strtol(const char *cp,char **endp,unsigned int base)
{
    if(*cp=='-')
        return -simple_strtoul(cp+1,endp,base);
    return simple_strtoul(cp,endp,base);
}
#endif
static int skip_atoi(const char **s)
{
    int i=0;

    while (isdigit(**s))
        i = i*10 + *((*s)++) - '0';
    return i;
}

#define ZEROPAD	1		/* pad with zero */
#define SIGN	2		/* unsigned/signed long */
#define PLUS	4		/* show plus */
#define SPACE	8		/* space if plus */
#define LEFT	16		/* left justified */
#define SPECIAL	32		/* 0x */
#define LARGE	64		/* use 'ABCDEF' instead of 'abcdef' */

static unsigned long long do_div(unsigned long long *n, unsigned base)
{
    unsigned long long res;
    res = (*n) %  (unsigned long long)base;

    *n = (*n) / (unsigned long long)base;

    return res;
}

static char * number(char * str, long long num, unsigned base, int size, int precision
                     ,int type)
{
    char c,sign,tmp[66];
    const char *digits="0123456789abcdefghijklmnopqrstuvwxyz";
    int i;

    if (type & LARGE)
        digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    if (type & LEFT)
        type &= ~ZEROPAD;
    if (base < 2 || base > 36)
        return 0;
    c = (type & ZEROPAD) ? '0' : ' ';
    sign = 0;
    if (type & SIGN) {
        if (num < 0) {
            sign = '-';
            num = -num;
            size--;
        } else if (type & PLUS) {
            sign = '+';
            size--;
        } else if (type & SPACE) {
            sign = ' ';
            size--;
        }
    }
    if (type & SPECIAL) {
        if (base == 16)
            size -= 2;
        else if (base == 8)
            size--;
    }
    i = 0;
    if (num == 0)
        tmp[i++]='0';
    else while (num != 0)
        tmp[i++] = digits[do_div((unsigned long long *)&num,base)];
    if (i > precision)
        precision = i;
    size -= precision;
    if (!(type&(ZEROPAD+LEFT)))
        while(size-->0)
            *str++ = ' ';
    if (sign)
        *str++ = sign;
    if (type & SPECIAL) {
        if (base==8)
            *str++ = '0';
        else if (base==16) {
            *str++ = '0';
            *str++ = digits[33];
        }
    }
    if (!(type & LEFT))
        while (size-- > 0)
            *str++ = c;
    while (i < precision--)
        *str++ = '0';
    while (i-- > 0)
        *str++ = tmp[i];
    while (size-- > 0)
        *str++ = ' ';
    return str;
}

/** %e, %f, %g are not implemented */
int _v_printf(int (*_write)(void*, const void *, ssize_t ), void* arg, const char *fmt, va_list args)
{
    int len;
    unsigned long long num;
    int i, base;

    char* str = 0;
    const char *s;

    int flags;		/* flags to number() */

    int field_width;	/* width of output field */
    int precision;		/* min. # of digits for integers; max
    number of chars for from string */
    int qualifier;		/* 'h', 'l', or 'L' for integer fields */

    int err;
    off_t out_len = 0;
    int pos = 0;
    char buf[ 1024 ];

#define WRITE(C)    do { buf[pos++] = (C); \
    if(pos == 1024 ) { \
    err = _write(arg, buf, 1024 );\
    if(err < 0) { if(str) free(str); return err; }\
    out_len += pos; \
    pos = 0; \
    } } while(0)

#define ALLOC_STR(MAX) (char *)malloc(((precision > field_width) ? ((precision > (MAX) ) ? precision : (MAX) ) : (field_width > (MAX) ) ? field_width : (MAX) )*sizeof(char));

    /* Loop through each character of the format*/
    for (; *fmt ; ++fmt)
    {
        /* Copy over non-format chars */
        if (*fmt != '%')
        {
            WRITE( *fmt );
            continue;
        }

        /* process flags */
        flags = 0;
    repeat:
        ++fmt;		/* this also skips first '%' */
        switch (*fmt) {
        case '-': flags |= LEFT; goto repeat;
        case '+': flags |= PLUS; goto repeat;
        case ' ': flags |= SPACE; goto repeat;
        case '#': flags |= SPECIAL; goto repeat;
        case '0': flags |= ZEROPAD; goto repeat;
        }

        /* get field width */
        field_width = -1;
        if (isdigit(*fmt))
            field_width = skip_atoi(&fmt);
        else if (*fmt == '*') {
            ++fmt;
            /* it's the next argument */
            field_width = va_arg(args, int);
            if (field_width < 0) {
                field_width = -field_width;
                flags |= LEFT;
            }
        }

        /* get the precision */
        precision = -1;
        if (*fmt == '.') {
            ++fmt;
            if (isdigit(*fmt))
                precision = skip_atoi(&fmt);
            else if (*fmt == '*') {
                ++fmt;
                /* it's the next argument */
                precision = va_arg(args, int);
            }
            if (precision < 0)
                precision = 0;
        }

        /* get the conversion qualifier */
        qualifier = -1;
        if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L') {
            qualifier = *fmt;
            ++fmt;
        }

        /* default base */
        base = 10;

        switch (*fmt) {
        case 'c':
            if (!(flags & LEFT))
                while (--field_width > 0)
                {
                    WRITE( ' ' );
                }
            WRITE( (unsigned char) va_arg(args, int) );
                while (--field_width > 0)
                {
                    WRITE( ' ' );
                }
            continue;

        case 's':
            s = va_arg(args, char *);
            if (!s)
                s = "<NULL>";

            len = strnlen(s, precision);

            if (!(flags & LEFT))
                while (len < field_width--)
                {
                    WRITE( ' ' );
                }
            for (i = 0; i < len; ++i)
            {
                WRITE( *s++ );
            }
            while (len < field_width--)
            {
                WRITE( ' ' );
            }
            continue;

        case 'p':
            if (field_width == -1) {
                field_width = 2*sizeof(void *);
                flags |= ZEROPAD;
            }
            str = ALLOC_STR( 12 );
            str[0]= '0';
            str[1]= 'x';
            s = number(str+2,
                       (unsigned long) va_arg(args, void *), 16,
                       field_width, precision, flags);
            len = s - str;
            s = str;
            for(i = 0; i < len; i++)
            {
                WRITE( *s++ );
            }
            free(str); str = 0;
            continue;

            /* From GNU documentation:
             "The %n conversion is unlike any of the other output conversions. It uses an argument which must be a
             pointer to an int, but instead of printing anything it stores the number of characters printed so far
             by this call at that location. The h and l type modifiers are permitted to specify that the argument
             is of type short int * or long int * instead of int *, but no flags, field width, or precision are permitted."
             http://www.gnu.org/manual/glibc-2.2.5/html_node/Other-Output-Conversions.html#Other%20Output%20Conversions
             */

        case 'n':
            if (qualifier == 'l') {
                long * ip = va_arg(args, long *);
                *ip = out_len + pos;
            } else {
                int * ip = va_arg(args, int *);
                *ip = out_len + pos;
            }
            continue;

            /* integer number formats - set up the flags and "break" */
        case 'o':
            base = 8;
            break;

        case 'X':
            flags |= LARGE;
        case 'x':
            base = 16;
            break;

        case 'd':
        case 'i':
            flags |= SIGN;
        case 'u':
            break;

        default:
            if (*fmt != '%')
            {
                WRITE( '%' );
            }
            if (*fmt)
            {
                WRITE( *fmt );
            }
            else
                --fmt;
            continue;
        }
        if (qualifier == 'L')
            num = va_arg(args, unsigned long long);
        else if (qualifier == 'l') {
            num = va_arg(args, unsigned long);
            if (flags & SIGN)
                num = (long) num;
        } else if (qualifier == 'h') {
            num = (unsigned short) va_arg(args, int);
            if (flags & SIGN)
                num = (short) num;
        } else if (flags & SIGN)
            num = va_arg(args, int);
        else
            num = va_arg(args, unsigned int);

        str = ALLOC_STR( 65 )
        s = number(str, num, base, field_width, precision, flags);
        len = s - str;
        s = str;
        for(i = 0; i < len; i++)
        {
            WRITE( *s++ );
        }
        free(str); str = 0;
    }
    out_len += pos;
    err = _write(arg, buf, pos);
    if(err < 0) return err;
    return out_len;
#undef ALLOC_STR
#undef WRITE
}

